https://gitlab.com/libtiff/libtiff/-/merge_requests/334

From 62a49eeb3f0c986c5fcbfc53cd3d7ef2a3fab9b3 Mon Sep 17 00:00:00 2001
From: Sam James <sam@gentoo.org>
Date: Sat, 21 May 2022 01:01:35 +0100
Subject: [PATCH] test/tiffcp-thumbnail.sh: skip test if tools aren't built

In Gentoo, we avoid building the tools for multilib (32-bit, x86) builds on
amd64/x86_64 because we only need the library to keep binary applications working.

This causes a test failure in just tiffcp-thumbnail.sh as the 'thumbnail'
binary isn't built. Skip it if unavailable as it's only a single test.

Fixes: https://gitlab.com/libtiff/libtiff/-/issues/421
--- a/test/tiffcp-thumbnail.sh
+++ b/test/tiffcp-thumbnail.sh
@@ -4,7 +4,12 @@
 #
 . ${srcdir:-.}/common.sh
 
+if [ ! -x "${TIFFCP}" ] || [ ! -x "${THUMBNAIL}" ] ; then
+	# https://gitlab.com/libtiff/libtiff/-/issues/421
+	exit 77
+fi
+
 outfile1=o-tiffcp-thumbnail-in.tif
 outfile2=o-tiffcp-thumbnail-out.tif
 f_test_convert "${TIFFCP} -c g3:1d" "${IMG_MINISWHITE_1C_1B}" "${outfile1}"
-f_test_convert "${THUMBNAIL}" "${outfile1}" "${outfile2}"
\ No newline at end of file
+f_test_convert "${THUMBNAIL}" "${outfile1}" "${outfile2}"
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